Water collected on surfaces such as decks, roofs, and terraces may be drained to prevent potentially damaging accumulations. A prior art drainage system is provided as an example in FIGS. 1A and 1B. The drainage system includes a roof 1 and a parapet 2 positioned around the perimeter of the roof 1. Scupper passageways extend through the parapet 2 and include primary scuppers 5 and secondary scuppers 7. When water collects at the roof surface 4, the water initially flows to the primary scuppers 5 positioned approximately level with or below the roof surface 4. Downspouts 6 are positioned to receive water from the primary scuppers 5 for additional directing of the water. The secondary scuppers 7 are positioned above the adjacent roof surface 4 at a height that may be defined by code or preferred engineering standards. The secondary scuppers 7 function to provide additional drainage points for accumulating water 21 as shown in FIG. 1B if the primary scuppers 5 or downspouts 6 become clogged or lack desired drainage capacity.